Alta Redshift MXR and MX on a Dyno - Riding Maps Demystified

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Administrator

I thought, wouldn't it me nice to dyno my two Redshifts? Of course it would!

I googled the web and found an interesting Dirt Bike magazine article with all the charts and even numbers of the 2018 model year 450cc motocross bikes. They used an FMF DynoJet dyno. So, I googled and called around and found (apparently) the same DynoJet dyno nearby.

Today I took my 2018 MXR and 2017 MX to run on that dyno. Both bikes were run in Modes 1 through 4.

We had problems exporting the numeric data files, I will have to follow up about this tomorrow, but here are the printouts:

Administrator

2) Map 3 is more powerful than Map 2, but only up until 30 mph. After that these two maps are identical.

3) Map 4 is in a category of its own. It is way-way more powerful than all other maps (I did not know that! Alta has not told us). If you are not using Map 4, then you are not using the full power of the Alta Redshift.

4) Comparing the MXR to the MX:
- The power is identical in all maps until about 20 mph
- From 20 to 37 mph the MXR and the MX are identical in Maps 1, 2 and 3.
- From 37 to 55 mph the MX is slightly more powerful than the MXR in Maps 1, 2 and 3.
- After 55 mph the MX shows a sudden power drop in Maps 1, 2 and 3.
- After 20 mph the MXR in Map 4 is 6-8 hp more powerful than the MX. But only in Map 4.
- No wonder I could not tell any difference between the two bikes in Maps 1, 2 and 3!

5) If Map 3 is not powerful enough at the top, but Map 4 is too jerky, then running Map 4 with a 14-tooth front sprocket (13-tooth for the MX) would create a "perfect Map 3", which is placed right between Map 2 and Map 4 through the entire speed range. The curve for Map 4 would shift/scale 16% to the right, reducing the power below 30mph and providing approximately the same power as Map 4 above 30mph, the point where the stock Map 3 signs off. The engine braking would drop 16% though.

6) In order to beat the Redshift MXR, the 450cc bikes would have to be at WOT, rev above 7,000 rpm, and shift perfectly (which is often impossible).

7) The horsepower curves are pretty flat, which means that the torque curves are highly digressive. The torque drops fast. This explains the excellent traction, the hill climbing ability, and the ability to drift and rear-steer at any speed.

Active member

So, I'm now curious to see an SM with stock gearing on the dyno as well. The MX hit the advertised 42hp at the rear wheel geared for about 63mph geared 12F/53R. The SM is shipping with 15F/50R and listed as 42hp at the countershaft. I wonder what it's putting to the ground?

Administrator

Now, the biggest revelation for me so far has been Map 4. If you are not using Map 4, then you are not using the full power of the Redshift. It is like never opening the throttle fully.

Riding in Map 4, but not opening the throttle fully, is almost the same thing.

Why do riders prefer other maps to Map 4? This is because Map 4 is too snappy below 30mph.

This is why gearing up when running Map 4 works so well. You get less max torque below 30mph, allowing you to pin the throttle wide open. At the same time it releases the full power of the Redshift at 30mph and above.

You would actually get more HP and torque above 30mph with this geared-up setup. It is an equivalent of running an ICE bike in the correct gear. Like when the 1st is too snappy you do not run a partial throttle, you short-shift into the 2nd gear, which gives you a smoother acceleration and more pull at higher speeds than the 1st gear could provide.

Well-known member

Alta suggests Map 4 as a hole shot mode. Anyone who has ridden in mode for in any length knows that it absolutely kills the battery. 1 is for absolute lugging, 2 is for actual riding, 3 is more torque-y for trail riding but drains battery quicker in MX scenarios and 4 is a "hole shot mode" meant for basically launches off the line but not for longevity. This is as explained from Alta and how I tend to ride.